The present invention relates to a monitoring apparatus for advising if an illumination condition of traffic signal lights is normal or abnormal, and a control apparatus for controlling the signal lights based on an advisory signal from the monitoring apparatus.
With traffic signal units provided for example at a road intersection or the like, if an illumination condition of the signal lights is abnormal, then a traffic conflict can result. In particular, if the green lights (referred to hereunder as G lights) for permitting people and vehicles to proceed, are simultaneously illuminated for the respective directions of the intersecting roads, an extremely dangerous situation results. To avoid this situation, monitoring for simultaneous illumination of the G lights for the respective directions of the intersecting roads has heretofore mainly involved using a hard logic, for example to detect the terminal voltage of the signal lights via a voltage transformer or the like.
With conventional simultaneous G light illumination detection methods, voltage transformers are connected across the terminals of the G lights, so that a voltage is produced in the respective voltage transformers when the G lights illuminate, the arrangement being such that when a G light pair for the respective directions of the intersecting roads are illuminated simultaneously, G light simultaneous illumination (danger condition) is advised by the presence of a voltage (corresponding to a high energy condition). That is to say, the arrangement is such that a danger condition is advised by a high energy condition. In this case, if a fault occurs where the output to the monitoring circuit itself, which includes for example the voltage transformer, has a fault giving zero, then there is a problem in that if a simultaneous illumination of the G light pair for the respective intersecting roads occurs, this cannot be advised.
Moreover, in most cases it has not been possible to reach a stage where the illumination condition of a plurality of signal lights is monitored by only monitoring for simultaneous illumination of a G light pair for respective intersecting roads.
In view of the above situation, it is an object of the present invention to provide a monitoring apparatus for fail-safe monitoring for abnormal conditions such as, simultaneous illumination of traffic proceed permit signal lights, or signal light burn-out. Moreover, it is an object of the invention to provide a signal light control apparatus, which uses such a fail-safe monitoring apparatus.
Accordingly, the monitoring apparatus for traffic signal lights according to the present invention comprises: a sensor device for detecting an illumination condition of traffic signal lights; and a judgment device for generating an output of logic value 1 corresponding to a high energy condition indicating a normal condition of the signal lights when, based on an output from the sensor device, the number of illuminated or non illuminated signal lights is a predetermined number, and generating an output of logic value 0 corresponding to a low energy condition indicating an abnormal condition of the signal lights when not the predetermined number.
With this construction, since when the signal lights are normal and thus safe, this can be advised by a high energy condition (logic value 1) while when the signal lights are abnormal and thus dangerous, this can be advised by a low energy condition (logic value 0), then when a fault occurs where the sensor device or judgment device gives a zero output, this dangerous situation can be advised. Hence reliability of the signal light monitoring can be improved.
The construction may be such that the judgment device generates an output of logic value 1 when the number of illuminated signal lights is a predetermined number, and generates an output of logic value 0 indicating a signal light burn-out fault when not the predetermined number.
If in this way judgment of a signal light burn-out fault is carried out from the number of illuminated lights, with a logic value 1 for when the signal lights are illuminated, then the output level goes to the low side with both a signal light burn-out fault, and a zero output fault for example in the sensor. Therefore it is possible to warn off danger, even in the case where both faults coincide.
The construction may be such that the output from the judgment device is output via an on-delay circuit having a delay time which is longer than an illumination period of the signal lights, or via a self-hold circuit with the output from the judgment device as a reset input signal, and a signal light power source switch on signal as a trigger input signal, which self-holds the trigger input signal.
In this way, even in the case where burn-out fault information appears intermittently in the illumination period of the signal light, this information output can be continuously advised until conditions return to normal.
Moreover, the construction may be such that the judgment device generates an output of logic value 1 when the number of non illuminated signal lights is a predetermined number, and generates an output of logic value 0 indicating a signal light simultaneous illumination fault where simultaneous illumination is not permitted, when not the predetermined number.
If in this way judgment of a signal light simultaneous illumination fault is carried out from the number of non illuminated lights, with a logic value 1 for when the signal lights are not illuminated, then the output level goes to the low side with both a signal light simultaneous illumination fault, and a zero output fault for example in the sensor. Therefore it is possible to warn off danger, even in the case where both faults coincide.
The construction may be such that the output from the judgment device is output via an on-delay circuit having a delay time which is longer than an illumination period of the signal lights, or a self-hold circuit with the output from the judgment device as a reset input signal, and a signal light power source switch on signal as a trigger input signal, which self-holds the trigger input signal.
In this way, even in the case where simultaneous illumination fault information appears intermittently in the illumination period of the signal lights, this information output can be continuously advised until conditions return to normal.
The construction is such that an illumination condition of respective signal lights for respective road directions of a two way intersection where two roads intersect is detected using sensor devices which output a binary logic signal, generating an AC signal and outputting a logic value 1 when a signal light is illuminated, and not generating an AC signal and outputting a logic value 0 when the signal light is not illuminated, and there is provided a judgment device which, based on the output conditions from respective sensor devices for each of the respective signal lights, generates an output of logic value 1 corresponding to a high energy condition when the signal lights are normal, and generates an output of logic value 0 corresponding to a low energy condition at the time of a simultaneous illumination of the signal lights where simultaneous illumination is not permitted.
Basically, the construction may be such that the judgment device comprises; a first adding circuit for adding the logic signals of the respective sensor devices for detecting an illumination condition of respective green lights indicating permission to proceed in the respective road directions, and a first level detection circuit for level detecting the addition value from the first adding circuit, the construction being such that the first level detection circuit generates an output of logic value 1 when the addition value is 1, and generates an output of logic value 0 when the addition value is 2. Consequently it is possible to monitor for simultaneous illumination of the green lights.
Furthermore, the construction may be such that the judgment device comprises the first adding circuit and the first level detection circuit of claim 19, and further comprises: a second adding circuit for adding the logical signals of the respective sensor devices for detecting an illumination condition of respective red lights for the respective road directions; a second level detection circuit for level detecting the addition value from the second adding circuit; a third adding circuit for adding the logical signals of respective sensor devices for detecting an illumination condition of yellow lights for the respective road directions and an output signal from the second level detection circuit; and a first logical sum operation circuit for carrying out a logical sum operation on the addition value from the third adding circuit and an output from the first level detection circuit, and the logical sum operation output is made a judgment output. Consequently, if the signal lights are normal in the illumination period of the signal lights, an output of logic value 1 is continuously generated so that safety can be advised.
In order to continuously generate an output of logic value 1 when the signal lights are normal, the construction may be such that the judgment device comprises the second adding circuit and the second level detection circuit of claim 20, and further comprises: a fourth adding circuit for adding the logical signals of respective sensor devices for detecting an illumination condition of green lights and yellow lights for the respective road directions; and a second logical sum operation circuit for carrying out a logical sum operation on the addition value from the fourth adding circuit and an output from the second level detection circuit, and the logical sum operation output is made a judgment output.
The construction may also be such that the signal lights for the same road of a two way intersection where two roads intersect are made one group, and for each group the illumination condition of a permit signal light indicating permission to proceed is detected using a sensor device which outputs a binary logic signal, generating an AC signal and outputting a logic value of 1 when a signal light is not illuminated, and not generating an AC signal and outputting a logic value 0 when the signal light is illuminated, and there is provided a judgment device which, based on the output conditions from the sensor device for each group, generates an output of logic value 1 corresponding to a high energy condition indicating the signal lights are normal, when at least one group shows a non illuminated condition, and generates an output of logic value 0 corresponding to a low energy condition indicating a simultaneous illumination fault when neither group shows a non illuminated condition.
In this way, danger can be reliably advised even in the case where a simultaneous illumination and a fault such as in the sensor occur at the same time.
In the case of only one permit signal light, that is to say, for simultaneous illumination detection of the green lights, the construction may be such that the judgment device comprises a third logical sum operation circuit for carrying out a logical sum operation on the logical output from the respective sensor devices for each respective group, and the logical sum operation output is made a judgment output. Moreover the judgment device may comprise: a fifth adding circuit for adding the logical outputs from the respective sensor devices for each respective group; and a third level detection circuit for level detecting the addition value from the fifth adding circuit, the construction being such that the third level detection circuit generates an output of logic value 1 when the addition value is 1 or more and generates an output of logic value 0 when the addition value is zero.
In the case of a plurality of permit signal lights for the respective groups, for example for simultaneous illumination detection of the green lights, yellow lights, and pedestrian green lights etc., then the construction may be such that the judgment device comprises: sixth and seventh adding circuits for respectively adding the logical outputs from the respective sensor devices for each respective group; fourth and fifth level detection circuits for respectively level detecting the addition values from the sixth and seventh adding circuits and outputting a logic value 1 when the addition values are respectively a maximum; and a fourth logical sum operation circuit for carrying out a logical sum operation on both outputs from the fourth level detection circuit and the fifth level detection circuit, and the logical sum operation output is made a judgment output. Moreover, the judgment device may comprise: eight and ninth adding circuits for respectively adding the logical outputs from the respective sensor devices for each respective group; a fifth logical sum operation circuit for carrying out a logical sum operation on the addition values from the eighth and ninth adding circuits; and a sixth level detection circuit for level detecting the logical sum output from the fifth logical sum operation circuit and outputting a logic value 1 when the logical sum output is a logic value of 2 or more.
Moreover, the sensor device may be a current sensor provided for each permit signal light, with a power supply line for the permit signal light wound around a saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level at the time of no power to the power supply line, and is received on the output side at a low level at the time of power supply. Alternatively the sensor device may be a voltage sensor provided for each permit signal light, which detects a terminal voltage of an illumination switch circuit disposed in a power supply line for the permit signal light.
In the case of a voltage sensor, if a simultaneous illumination fault occurs due to a short circuit fault between the power supply lines for the signal lights, then this can be detected.
The construction of the voltage sensor may basically involve a series circuit of a first photocoupler for switching an AC current from an illumination power source using a high frequency signal from a high frequency signal generator, and a second photocoupler for receiving an AC signal from the switched illumination power source, connected in parallel across the terminals of a switching circuit for signal light illumination which is connected in series with the signal light.
If a current sensor is used for the sensor device, with all power supply lines for the permit signal lights of the same group wound around one saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level when no current flows in all the power supply lines, and is received on the output side at a low level when a current flows in at least one power supply line, then the number of current sensors can be reduced.
Moreover, the construction may be such that in the case of a voltage sensor for the sensor device, then basically this involves a series circuit of a first photocoupler for switching an AC current from an illumination power source using a high frequency signal from a high frequency signal generator, and a second photocoupler for receiving an AC signal from the illumination power source switched by the first photocoupler, connected in parallel across the terminals of an illumination switching circuit for one permit signal light, together with a plurality of series circuits constituted by photocouplers, each of which connected in parallel across the terminals of an illumination switching circuit for another permit signal light, with the second photocoupler and the series circuits constituted by photocouplers cascade connected, and an output from the final stage series circuit made the sensor output.
Moreover with the monitoring apparatus, in monitoring for a simultaneous illumination fault of the signal lights of a three way intersection where three roads intersect, the signal lights for the same road are made one group, and for each group, the illumination condition of a permit signal light indicating permission to proceed is detected using a sensor device which outputs a binary logic signal, generating an AC signal and outputting a logic value of 1 when a signal light is not illuminated, and not generating an AC signal and outputting a logic value 0 when the signal light is illuminated, and there is provided: tenth, eleventh and twelfth adding circuits for respectively adding the logical signals from the sensor devices for each group; seventh, eight and ninth level detection circuits for respectively level detecting the addition values from the respective adding circuits and generating an output of logic value 1 when the respective addition values are a maximum; a thirteenth adding circuit for adding the logical outputs from the respective level detection circuits; and a tenth level detection circuit for outputting a logic value 1 indicating normal signal lights when the addition value of the thirteenth adding circuit is 2 or more, and generating an output of logic value 0 indicating a simultaneous illumination fault when the addition value is 1 or less.
In this way, it is possible to monitor for a simultaneous illumination fault of the signal lights of a three way intersection.
In the case of monitoring for a simultaneous illumination fault of the signal lights of a three way intersection where three roads intersect, the illumination condition of the respective permit signal lights indicating permission to proceed is respectively detected using sensor devices which output a binary logic signal, generating an AC signal and outputting a logic value 1 when a signal light is not illuminated, and not generating an AC signal and outputting a logic value 0 when the signal light is illuminated, and there is provided: a fourteenth adding circuit for adding the sensor outputs corresponding to the respective permit signal lights for the first direction and second direction roads; a fifteenth adding circuit for adding the sensor outputs corresponding to the respective permit signal lights for the second direction and third direction roads; a sixteenth adding circuit for adding the sensor outputs corresponding to the respective permit signal lights for the third direction and first direction roads; and an eleventh level detection circuit for generating an output of logic value 1 indicating normal signal lights when the addition value of the respective adding circuits is 6, and generating an output of logic value 0 indicating a simultaneous illumination fault when the addition value is 5 or less.
Furthermore, for the control apparatus of the present invention for controlling the illumination of traffic signal lights, the construction may comprise: a signal light monitoring circuit provided with, a sensor device for detecting an illumination condition of respective signal lights, and a judgment device for generating an output of logic value 1 corresponding to a high energy condition indicating a normal condition of the signal lights when, based on an output from the sensor device, the number of illuminated or non illuminated signal lights is a predetermined number, and generating an output of logic value 0 corresponding to a low energy condition indicating an abnormal condition of the signal lights when the number is not the predetermined number; and a signal light power supply control circuit which supplies power to the signal lights when an output of logic value 1 is generated from the signal light monitoring circuit, and which stops power supply to the signal lights when an output of logic value 0 is generated.
In this way, the illumination control for the signal lights can be carried out in a fail-safe manner.
The signal light monitoring circuit may comprise: a sensor device constructed so as to generate an AC signal at the time of non illumination of a signal light, and not to generate an AC signal at the time of illumination; and a judgment device which generates an output of logic value 1 when the number of non illumination outputs from the sensor device is a predetermined number, and generates an output of logic value 0 indicating a signal light simultaneous illumination fault where simultaneous illumination is not permitted, when not the predetermined number.
Moreover, the signal light power supply control circuit may have an electromagnetic relay having relay contact points disposed in series in the power supply lines for the respective signal lights, the construction being such that the electromagnetic relay is placed in a non excited condition with the contact points open, based on an output of logic value 0 indicating simultaneous illumination of the signal light monitoring circuit.
Furthermore, the signal light power supply control circuit may incorporate: a first self-hold circuit with a signal light power source switch on signal as a trigger input signal, and an output from the signal light monitoring circuit as a reset input signal, which self-holds the trigger input signal, the construction being such that the electromagnetic relay is excited and the contact points thus closed with an output of logic value 1 from the self-hold circuit when a reset input signal of logic value 1 indicating normal signal lighting from the monitoring circuit, and a trigger input signal of logic value 1 due to the power source switch on signal are input together.
Furthermore, the construction may be such that the signal light power supply control circuit incorporates: a signal light flash command circuit which outputs to an illumination control circuit, a flash command for a yellow light and a red light for intersecting roads when an output of logic value 0 indicating simultaneous illumination of the, signal lights is generated from the signal light monitoring circuit so that the output from the first self-hold circuit is cancelled; a flash monitoring circuit for monitoring if a flash operation of the yellow light and red light is normal, based on the flash command from the signal light flash command circuit; and an electromagnetic relay control circuit which de-energizes the electromagnetic relay to open the contact points and stop the signal light power supply, based on an output from the flash monitoring circuit when the flash operation for the yellow light and the red light is abnormal.
Moreover, the electromagnetic relay control circuit may comprise: a second self-hold circuit with a signal for a fall in the output of logic value 1 from the signal light monitoring circuit as a trigger input signal, and a monitoring output from the flash monitoring circuit as a reset input signal, the construction being such that when the flash operation for the yellow light and the red light is normal at the time of signal light simultaneous illumination, the trigger input signal and the reset input signal both become a logic value 1 so that the excitation of the electromagnetic relay is maintained by means of an output from the second self-hold circuit.
Moreover the construction may comprise: respective saturable magnetic cores with respective signal light power supply lines provided for each of a plurality of signal lights connected in parallel with each other to a common power supply line, wound thereon as primary windings; a transformer with second windings for impedance detection wound on the respective saturable magnetic cores and connected in series with each other, acting as load for a secondary winding thereof and which receives a high frequency signal from a high frequency signal generator in a primary winding thereof, and a level detection circuit which generates an output of logic value 1 indicating normal signal lights when an output signal level of the transformer is equal to or above a predetermined level as a result of an output signal change due to a change in impedance for the transformer, and generates an output of logic value 0 indicating a signal light burn-out fault when lower than the predetermined level.
In this way, it is possible to detect a signal light burn-out fault in the case where a plurality of signal lights are connected in parallel to a common power supply line.
Moreover, the monitoring apparatus may be one wherein an illumination condition of respective signal lights of an intersection where a plurality of roads intersect is detected using sensor devices which generate an AC signal at the time of non illumination of a signal light and which do not generate an AC signal at the time of illumination of the signal light, and wherein an AC signal level at the time of non illumination from a sensor device for detecting the illumination condition of a vehicle green light and a pedestrian green light, is made different from an AC signal level at the time of non illumination from a sensor device for detecting an illumination condition of a yellow light, and wherein there is provided a judgment device which, based on the outputs from the respective sensor devices, distinguishes and warns between respective simultaneous illumination faults of the vehicle green light pairs, and the vehicle green lights and the pedestrian green lights, and respective simultaneous illumination faults of the vehicle green lights and the yellow lights, and the pedestrian green lights and the yellow lights.
In this way, it is possible to monitor and distinguish between a simultaneous illumination fault of the green light pairs or the green light and the yellow light, and hence it is possible to detect carefully signal light abnormalities.
Moreover the invention provides a monitoring apparatus for traffic signal lights for monitoring for simultaneous illumination faults in traffic signal lights where illumination is controlled with the green, red and yellow signal lights of respective signal units for an intersection where a plurality of roads intersect, connected in parallel with one common power supply line, the construction being such that current sensors are used, each with the power supply line for the signal light wound on a saturable magnetic core such that an excitation signal for the saturable magnetic core input from a high frequency signal generator is received on an output side at a high level at the time of no power to the power supply line, and is received on the output side at a low level at the time of power supply, and the common power supply lines for the signal units and the red light power supply lines are wound in opposite directions to each other on the saturable magnetic cores of the respective current sensors provided for each signal unit for the respective road directions, and the AC signal level of the respective current sensors is added by an adding circuit, and the added signal level is detected by a level detection circuit, the level detection circuit generating an output of logic value 1 indicating normal when the addition signal level is equal to or above a previously set predetermined level, and generating an output of logic value 0 indicating a simultaneous illumination fault when lower than the predetermined level.
In this way, it is possible to monitor for a simultaneous illumination fault of the permit signal lights for permitting traffic to proceed, using a common line and the red light power supply line.
With a control apparatus for controlling the illumination of signal lights for a two way intersection where two roads intersect, the construction may be such that the illumination condition of respective permit signal lights for permitting traffic to proceed in the respective road directions is detected using sensor devices which generate an AC signal at the time of non illumination of the signal lights and which do not generate an AC signal at the time of illumination, and there is provided: a first electromagnetic relay which is excited by an output signal from a first sensor device for detecting an illumination condition of a permit signal light on one road; and a second electromagnetic relay which is excited by an output signal from a second sensor device for detecting an illumination condition of a permit signal light on the other road, and wherein relay contact points for closing a circuit at the time of excitation of the second electromagnetic relay are disposed in series in a power supply line for the permit signal light for the one road, and relay contact points for closing a circuit at the time of excitation of the first electromagnetic relay are disposed in series in a power supply line for the permit signal light for the other road.
In this way, when the green light for one road direction of the intersecting roads is illuminated, the illumination current for the green light for the other road direction can be shut off. Moreover, since a time difference exists between the reciprocal illuminations of the green lights, then the illumination current for the signal lights is not shut off by the on and off switching of the electromagnetic relay contact points.